Needle clamp for sewing machines



March 7, 1961 R, JOHNSON NEEDLE CLAMP FOR SEWING MACHINES Original Filed Np V. 29, 1954 2 Sheets-Sheet 1 Ralph E. Johnson ATTORNEY BY wdz/m WITNESS l;

wzwfi March 7, 1961 R. E. JOHNSON NEEDLE CLAMP FOR SEWING MACHINES Original Filed Nov. 29, 1954 2 Sheets-Sheet 2 HVVENTOR Ralph E. Johnson ATTORNEY 2,973,733 I NEEDLE CLAMP FOR SEWING MACHINES Ralph E. Johnson, Mountainside, N.J., assignor to The Singer Manufacturing Company, Elizabeth, N J., a corporation of New Jersey Original application Nov. 29,, 19,54, Ser. No. 471,766,

now Patent No. 2,862,468, dated Dec 2, 1958. Divided and this application Dec. 7, 1956, Ser. No. 626,908 4 2 Claims. (Cl. 112226) This invention relates to devices for clamping the needle of a sewing machine in working position relative to the needle-bar and has for an object to provide a needle-clamp which is simple in construction, inexpensive of manufacture and easy to assemble and which will securely clamp the needle yet permit the latter to be readily removed when desired.

Yet another object of the present invention is to provide a sewing machine with a novel means for clamping either one or a pair of needles to a reciprocatory needlebar mechanism,

With the above and other objects in View, the invention comprises the devices, combinations and arrangements of parts hereinafter described in connectionwith the accompanying drawings which illustrate a preferred embodiment of the invention from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the drawings,

Fig. 1 represents a side elevational view of a portion of a sewing machine needle-bar and its associated needle-clamp.

Fig. 2 represents a sectional view taken substantially along the line 2-2 of Fig. 1.

Fig. 3 represents a left side elevational view of the mechanism disclosed in Fig. 1.

Fig. 4 represents a sectional view taken substantially along the line 4 4 of Fig. 1.

Fig. 5 represents a sectional view taken substantially along the line 5-5 of Fig. 1.

Fig. 6 represents a vertical sectional view of the mechanism disclosed in Fig. 1.

Fig. 7 represents a perspective view of a needle-clamp guide element which is adapted to be secured to the needle-clamp mechanism in the manner as is best disclosed in Fig. 1.

Fig. 8 represents a fragmentary top plan view of a sewing machine rotary loop-taker mechanism and shows the relation between twin needles and the loop-taker.

Fig. 9 represents a similar view to Fig. 5 but shows the needle-lamp as provided with a pair of needles.

Fig. 10 is similar to Fig. 5 but illustrates the needleclamp as being provided with two needles instead of Fig. 11 represents a right side elevational view of the needle-bar shown in Fig. 1. V

Fig. 12 represents a side elevational view of a typical ype of sewing m hin ne dle w ch ma b mpl with the present needle-clamp. i

The following detailed description relates to devices Patented Mar. 7, 1961 for clamping one or more needles to a sewing machine of the type disclosed in my co-pending application Se rial No. 471,766, filed November 29, 1954, now Patent No. 2,862,468, granted December 2, 1958, of which this application is a division. 1

As is shown in Figs. 1 to 6, inclusive, and Fig. 11, a sewing machine needle bar 15, at its lower portion, is provided with means for removably carrying an eyepointed needle 16 which cooperates with a rotary loop taker in the formation of stitches. More specifically, the needle-bar comprises a right cylindrical member 15 whose lower end portion is formed with a needle-shank receiving slot generally designated by the numeral 17. As may be seen in Figs.g6 and 11, intersecting the slot 17 is a second slot 18, which breaks through one cylindrical wall portion of the needle-bar 15. The slots 17 and 18 form a needle-shank receiving seat which is formed in part at least by a pair of substantially intersecting angularly disposed fiat walls 19 and Zil. Surrounding the lower portion of the needle-bar 15 and the lower portions of the intersecting slots 17 and 18 is a cylindrical clamping band generally designacd by the numeral 21, which band is provided with a vertical bore 22 in which is slidingly received the neadle-bar 15. One portion of the clamping band 21 is formed as a projecting boss 23 p o w h a th e de or 24 n hich is c ed a thumb screw 25 whose inner end portion is formed in the manner of a come as at 26, From Fig, 5, it is to be particularly observed that. the longitudinal axis of h c w 25 nc d s w th t a of th boss 2. and i laterally nf sd m th sne t ina ax o t e n sdle-bar 15. e

The clamping band 21 is rigidly secured to the needler 15 by ean i a sc e whic P se d ec y through a first aperture 28 in the band to be threaded in an aperture 295 in an Opposite bandwall. Also, the screw 27 passes through an aperture 36 formed directly in the needle-bar 15 so that the screw will lock the band and needle-bar together as an integral unit.

The present needle clamp is adapted to receive a sewing needle 16 of a conventional type having a shank portion formed as a slab-sided right circularcylinder with the slabhed side 31 being disposed substantially on an opposite side of the needle from the elongated groove 32 and at the same side as the short groove 33. This is a conventional type of sewing needle which must be accurately positioned relative to its associated iooptaker so as to insure the formation of proper stitches. In any sewing machine, it is essential that the point of the needle must always pass a certain fixed distance away from the loop-taker. In order to insure passage of the needle at this fixed distance from the loopvtakcr, the point of the sewing needle must always bear a certain fixed relation to the needle-bar. It is standard practice in the art for the shank of a sewing needle to be provided with a slabbed side -31 (see Fig. 12) which lies in a plane a fixed distance from the needle point. The same fixed distance is maintained regardless of the needle size. By placing the slabhed side 31 of the needleshank against a flat surface 19 (see Figs. 5 and Q) on the needle-bar 15, the correct distance between the n l nd the loopke bea 4' are i 8) w ll a ways be correctly maintained.

R ferrin t i 2 it ou d b not d ha he Gra ssectional width h of the needlershank is the minimum diametral dimension of the shank while the width d is the maximum diametral dimension.

As is perhaps best illustrated in Figs. 5 and 6, the needle 16 is adapted to be positioned within a needleshank receiving slot 17 at the juncture of the two angularly disposed walls 19 and 20 and with the slabbed side 31 of the shank disposed flat against the wall 19. With the needle in this position, the'thumb screw may be advanced into the shank-receiving slot so that the conical head 26 will engage a peripheral rounded wall of the needle thereby to force the same into the pocket formed by the angularly disposed walls 19 and 20. In this position, the longitudinal axis of the needle should correspond substantially with that of the needle-bar 15.

Referring to Fig. 6, it is to be particularly observed that the needle 16 is adapted to be inserted upwardly into the shank-receiving slot 17 until the needle engages the screw 27, which functions as an abutment stop for the needle to insure that the latter is set at the requisite height within the needle-bar 15.

Associated with the clamping band 21 is a needlethread guide member generally designated by the numeral 35, which comprises an apertured head portion 36 which is secured directly against the clamping band by means of the screw 27 in a manner as is best illustrated in Fig. 6. With the member 36 positioned against the clamping band 21, it is to be observed that projecting from the head portion 36 is a needle-thread guide loop in the form of a U-shaped finger 37 and projecting from the lower portion of the member is a substantially C-shaped member 38 which is adapted substantially to surround the lower portion of the needle-bar 15 in a manner as is best disclosed in Fig. 4. An intermediate portion of the loop 38 is provided with an indentation 39 into which the needle thread is adapted to be trained so that the latter may function as a needle-thread guide.

The present needle clamp is designed in a manner so that not only may it accommodate a single needle for the purpose of straightaway or zigzag stitching as the case may be, but the clamp is also designed to accommodate two needles which are often employed in the production of various types of decorative straightaway or zigzag stitching.

In order to accommodate two as opposed to a single needle, the thumb screw 25 may be backed away and thereafter two similar needles 16 and 40 may be inserted into the needle-shank receiving slot 17 in a manner such that the flattened or slabbed portions 31, 31 will be positioned against the slot wall 19 and thereafter the thumb screw 25 may be advanced toward the needles to the end that the conical end 26 will engage the needle 40 so as to bias both needles toward the juncture of the slot walls 19 and 20, thereby to lock the needles in position with the uppermost portions of the needle shanks positonied in engagement with the abutment or gauge screw 27.

From the above, it is to be appreciated that the present needle clamp will accommodate one or two needles without requiring any changes in the clamp structure or any adjustment thereof with the exception of the manuvering of the thumb screw 27.

Although the present needle clamp may be employed in conjunction with any standard type of sewing machine, it has been particularly designed for use with a sewing machine employing a circularly moving loop-taker having a loop-seizing hook mounted to move about an upright axis. More specifically, the present clamp has been designed to be used in connection with a loop-taker of the type in which the needles are adapted to descend within the confines of the loop-taker ring for the purpose of presenting their respective needle loops to .a loop-seizing beak which travels in a path which completely circumscribes ,the several needles. In this connection, reference may be had to Figs. 8 and 9 of which the former illustrates a rotary loop-taker ring 41 having a loop-seizing beak 34 which is rotated about a pair of needles 16 and 40 which, when they ascend through the work, throw out a pair of needle loops which will be seized by the loopseizing beak 34.

In order that the twin needles will be positioned in an optimum relation with respect to the loop-seizing beak 34, the wall 19 of the needle-shank receiving slot 17 is formed as a plane which is disposed in a substantially tangential relation with the circular path traveled by the loop-taker beak 34, which path is illustrated by the dotted line 42 of Figure 9. It is to .be particularly observed that the opposing slot walls 19 and 43 are each disposed at a slight angle to the line which is drawn at right angles to the direction of work feed, which line in Fig. 9 is indicated by the line 44-44. With the walls 19 and 43 so disposed it will be observed that the right-hand needle 40 will be located slightly behind the left-hand needle 16 relative to the direction of work feed, which distance between the two needles is represented by the letter Z in the Figure 9. In actual practice, it has been found that this distance may be in the order of seven thousandths of an inch. As illustrated in Fig. 9, the are 42, which substantially represents the path of loop-seizing beak movement, is drawn about the radius struck from the axis of the rotary loop-taker, and is represented in Fig. 9 by the letter R.

In connection with the above described needle-clamp, it is to be particularly understood that when two needles are to be employed in conjunction therewith the left-hand needle 16 is located in a position within the needle-bar 15 which is exactly the same position as is taken by the needle when it is singly employed. However, in machines of the type disclosed in my co-pending application Serial No. 471,766, the twin needles may be adjusted laterally so that they will normally straddle the center work seam line. This adjustment is made by shifting the lower end of the needle-bar 15 to the left by way of the usual sewing machine needle-bight control handle. Thereafter, the twin needles may be employed for producing straight or zigzag stitches in conjunction with the rotary loop-taker.

Having thus described the nature of the invention, what I claim herein is:

1. In combination, a sewing needle having a shank formed as a slab-sided right circular cylinder having a major and a minor diametral cross-sectional dimension; and a sewing needle clamp comprising, an elongated needle-bar formed in one end portion thereof with a needle-shank receiving slot elongated lengthwise of the longitudinal axis of the needle-bar and formed with a pair of opposing parallel side walls and a substantially flat bottom wall angularly intersecting the two side walls, the two side walls being spaced apart a distance substantially equal to the minor diametral dimension of the needle, a clamping band encircling the slotted end of the needle-bar, a needle clamping screw threaded within the band and extending crosswise of the needle-bar and into the slot toward the bottom wall with the longitudinal axis of the screw being offset with respect to a plane equidistantly disposed between the parallel side walls of the slot, and a conical shaped needle-engaging head formed upon that end of the needle-clamping screw disposed within the slot so as directly to engage the needle.

2. In combination, a pair of sewing needles each having a shank formed as a slab-sided right circular cylinder having a major and a minor diametral cross-sectional dimension; and a sewing needle clamp comprising, an elongated needle-bar formed in one end portion thereof with a needle-shank receiving slot elongated lengthwise of the longitudinal axis of the needle-bar and formed with a pair of opposing parallel side walls and a substantially flat bottom wall angularly intersecting the two side walls, the two side walls being spaced apart a distance substantially equal to the minor diametral dimension of the needle and the'depth of the slot being substantially equal 5 to the sum of the major diametral dimensions of the pair References Cited in the file of this patent of needles, a clamping band encircling the slotted end of UNITED STATES PATENTS the needle-bar, a needle clamping screw threaded within the band and extending crosswise of the needle-bar and fi B into the slot toward the bottom wall W h h lollgitudi- 5 1725916 it A 27 1929 11211 axis of the screw being offset with respect to a plane 2698589 Johnson i 1955 equidistantly disposed between the parallel side walls of the slot and a conical shaped needle-engaging head FOREIGN PATENTS formed npon that end of the needle-clamping screw dis- 430 Great Britain of 1865 posed within the slot so as dlrectly to engage one of the 10 997,130 France Jan. 2, 1952 two needles. 497,498 Italy Sept. 14, 1954 

